This project is designed to achieve two aims: 1) to investigate a new (Bloom 1970, 1973; Bowerman 1973) the question of what knowledge best characterizes the linguistic competence of the one- and two-word speaker, and 2) introduce a new method for studying language comprehension that requires only minimal overt responding by the child. This method can be used more generally to chart the ontogeny of linguistic constructs. The method (currently used to study infants' intermodal perception) is adopted from Spelke (1976). An infant sits in front of two rear-projected simultaneously presented filmed events. A sound source located to the rear and center of the films delivers and auditory stimulis consistent with only one of the films. Infant preference forthe film that matches the auditory stimulis is the dependent measure. In the proposed, linguistic stimuli paired with filmed events will serve as the independent variables. With this procedure we expect to determine whether one- and two-word speakers a) abstract relational meaning from two lexical terms (i.e., perceive items like "kiss dog: as an integrated unit); b) posses some internal grammar and that surface forms like "mommy tickle" are distinguished from surface forms like "tickle mommy"; and c) have underlying linguistic categories that are exclusively semantic in nature (agent - action - recipient or are syntactic (subject - verb - object) as well.